قائمة الطعام
The impurities found in the original kaolinite used in this study (muscovite, anatase and quartz) are observed in all calcined samples. Both pyrite and troilite …
The XRD spectrum of FeS 2 NWs and NTs within the alumina matrix are shown in Fig. 2.Sulfur vacancies and phase impurities (such as FeS, Fe 1−x S, and marcasite FeS 2) have been cited as potential problems for pyrite solar cells, as these phase impurities have small band gap that could lower V OC even if present in low …
Pyrite is a commonly found, naturally occurring mineral that is found in the ground and also known as iron pyrite (FeS2). Pyrite when present in rocks in low levels is generally fine. However ...
Iron pyrite (FeS 2) is an important source of iron and sulfur and is the most abundant, non-toxic, naturally occurring sulfur mineral found in the Earth's crust.The iron pyrite crystal structure consists of a face centered cubic lattice [], where each iron atom is octahedrally coordinated by six sulfur atoms and each sulfur atom is tetrahedrally …
Cobalt pyrite (CoS 2) and related materials are attracting much attention due to their potential use in renewable energy applications.In this work, first-principles studies were performed to investigate the effects of various neutral defects and ion dopants on the structural, energetic, magnetic and electronic properties of the bulk CoS 2.Our …
Pyrite samples synthesized with As, Co, or Ni impurities and without added impurities were oxidized in batch and mixed flow-through reactors in the presence of 1 mM ferric iron, at pH 2.
To understand the effects of these impurities on the electronic structure and reactivity of pyrite would be helpful to solve the problems which might be encountered in pyrite flotation practice. 2 Computational details 2.1 Pyrite structure Pyrite (FeS 2 ) possesses a rocksalt type structure and belongs to the space group 3 6 PaT h, with the …
Abstract—For the first time, EPMA and LA-ICP-MS data were obtained for the Kyuchus Au–As–Sb–Hg deposit on variations in the grades and zonal distribution of gold and other impurity elements in gold-bearing sulfides of disseminated ores. Two types of zoning have been found in pyrite: (1) zoning with the central zone depleted in …
Section snippets Samples. The pyrite used in this study is from two sources. Most samples were synthesized in our laboratory where pyrite crystals are grown with chemical vapor transport (CVT) in sealed evacuated quartz tubes in a temperature gradient of 700–550 °C over 16 cm using FeBr 3 as a transport agent (Lehner et al., …
A theory of disordered binary alloys A x B 1−x (A = Ni, Co; B = Fe; x∼0.06) is used to determine the changes in the electronic structure and magnetic properties of body centered cubic (BCC) iron induced by doping with nickel and cobalt impurities. This approximation is an extension of the cluster-Bethe lattice method, in which we …
Recent reports have shown evidence of phosphorus and cobalt as prospective dopants for improved optoelectronic properties and charge separation. Here, we demonstrate the …
Marine sediment is the most significant "sink" of iron sulfide. Framboidal pyrite can be formed in the synsedimentary process, very ... and the low limit of impurities level in a single crystal is approximately equal to the top limit of impurities level in pyrite aggregates ... Glob. Planet. Chang. 2010, 71, 109–123. [Google Scholar ...
The volatile impurities are removed. Sulphur, phosphorus, arsenic, and antimony which are present as an impurity are removed as volatile oxides. S + O 2 → SO 2. P 4 + 5O 2 → 2P 2 O 5. 4As + 3O 2 → 2As 2 O 3. The copper pyrite is partly converted into sulphides of copper and iron. 2CuFeS 2 + O 2 → Cu 2 S + 2FeS + SO 2. 2FeS + 3O 2 → ...
The production of the iron rich solution was carried out in three cylindrical columns (30 cm height × 7 cm diameter) containing 1 kg of pyrite concentrate where 1 L of water was added in each column and pumped through the particles in close circuit, for a period of 11 weeks (Fig. 1).Bacteria inoculums were added in the system to accelerate …
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Yet these values remain significantly higher, by 0.5–2‰, than equilibrium isotope fractionation inferred from β-factors of pyrite and the dominant iron chloride species in solution FeCl 2 (H 2 O) 2 0 (aq), generated in this study using Density Functional Theory (DFT) modeling (Δ 57 Fe FeCl 2 (H 2 O) 2-pyrite ≈ –1.25 ± 0.25‰ at 300 ...
Abstract. Synthetic pyrite crystals doped with As, Co, or Ni, undoped pyrite, and natural arsenian pyrite from Leadville, Colorado were investigated with …
1 Introduction. 2 Properties of pyrite and associated iron sulphides. 2.1 Pyrite. 2.1.1. Structure. 2.1.2. Composition. 2.1.3. Semi conductivity. 2.1.4. Thermodynamic …
1. Introduction. Iron pyrite has gained extensive research interest in the photovoltaic cell due to its high optical absorption (∼ 10 5 c m − 1 f o r h ν > 1.4 e V) and its photocatalytic, wherever iron pyrite is beneficial for the development of high power energetic solar cells [].However, it is a good candidate for photoelectrochemical and photovoltaic cells due to …
Pyrite enriched in Co is an n-type semiconductor with low resistivity and high carrier mobility, while arsenian pyrite tends to be p-type and have higher resistivity.
Sparta, Randolph County, Illinois. Sparta is a hidden gem in Illinois that offers a rich playground for the discovery of pyrite. Its geology is deeply tied to its limestone-rich bedrock and the presence of shale layers. Pyrite often forms in these sedimentary rocks due to the interplay of iron and sulfur.
The coordination chemical model (Fig. 1) for a mononuclear iron site on a pyrite surface was constructed from the highest resolution crystal structure (R value of 0.0173, ICSD # 109377) of cubic pyrite with a lattice constant of 5.416 Å (Rieder et al. 2007). In this model, the central Fe 2+ ion was coordinated by persulfhydryl ligands …
2.2 Mineralogical Assemblage. For the numerical simulations, the mineral assemblages of the caprock and the reservoir were defined using the literature data. The caprock minerals were taken from Gaus et al. and the reservoir minerals from Kjøller et al. (), who described the mineralogy of the sandstone Gassum reservoir.The caprock is …
Fool's gold, or pyrite, is made of worthless iron disulfide, but can contain tiny amounts of the real thing. Using an 'atom probe', research has uncovered a new way gold atoms can hide in ...
Pyrite samples synthesized with As, Co, or Ni impurities and without added impurities were oxidized in batch and mixed flow-through reactors in the presence of 1 mM ferric iron, at pH 2. Six samples from each dopant population were used to provide a statistically robust comparison; two natural samples from Leadville, CO (major …
1. Introduction. Pyrite, a nearly inexhaustible and low-cost material, has been used for gems and medicinal materials by human beings since ancient times [1].It has a dramatically large light absorption coefficient (greater than 10 5 cm −1) and a modest band gap, close to 1 eV, making it a promising photovoltaic material.Some researchers …
Section snippets Experimental procedure. Single crystals of iron pyrite FeS 2 were grown by the chemical vapor transport method [1], [7], [17] using ICl 3 as a transport agent. Prior to the crystal growth, quartz tubes containing ICl 3 and the elements (Fe: 99.95% pure, S: 99.999%) were evacuated and sealed. The quartz tube was placed in a …
This study does not report oxidation rates or mechanisms, but rather documents the electrical properties of natural pyrite containing impurities at concentrations that were previously difficult to measure. The compositional heterogeneity is also …
taining pyrite impurities were studied to validate the results obtained from the model systems. The natural clay samples were dried at 105 C for 72 h and subsequently ground in a disc mill for 30 ...
Its photovoltaic possibilities deepen its Earth abundance and nontoxicity. Iron pyrite is not only used in solar cells applications, it has interesting other …
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